There is a trend to integrate electronic functionality in the form of intelligent sensors at the tip of a minimally invasive medical instrument. These sensors can help the physician to guide the medical instrument through the body, or can allow for a more accurate diagnosis. For example, the use of a sensor, such as an optical camera or ultrasound transducer, is well-known at the tip of an endoscope. However, such electronic functionality is also envisioned for smaller medical instruments, such as catheters or (catheter) guide wires.
For example, the paper “Flex-to-Rigid (F2R): A Novel Ultra-Flexible Technology for Smart Invasive Medical Instruments”, Benjamin Mimoun, Vincent Henneken, Ronald Dekker, published in “Stretchable Electronics and Conformal Biointerfaces (Mater. Res. Soc. Symp. Proc. Volume 1271E, Warrendale, Pa., 2010), paper 1271-JJ05-09” (see also ectm.ewi.tudelft.nl/linkto/ectm_publications.php), which is incorporated by reference herein, discloses a technology for the fabrication of partially flexible miniature sensors interconnected by ultra-flexible interconnects, in particular for use in a smart or minimally invasive medical instrument.
Given the small size of such a sensor or sensor arrangement, generally no data compression hardware can be included at the distal tip of the medical instrument. Therefore, a relatively high data rate of sensor data, for example from an ultrasound transducer or camera, is generated. For a high data rate, generally an electrical wire with a well defined characteristic impedance is required, such as a coaxial cable. However, the smallest coaxial cable has a diameter of several hundreds of μm. For example only a single coaxial cable may fit in a minimally invasive medical instrument (e.g. a guide wire having a 300 μm diameter), which limits the data rate. Thus, a high data rate has so far required the use of electrical wires, extending from the distal end to the proximal end of the medical instrument, which require a lot of space. The use of such wires requiring a lot of space, however, makes the medical instrument larger which is not desirable, in particular for a minimally invasive medical instrument. Therefore, so far a tradeoff between the data rate and the size of the medical instrument had to be made.